The instant invention relates to a sheet accumulator with continuously moving belts, and more particularly to a rail support mechanism for supporting the belts and paper sheets at a document queuing station.
Various document processing systems, such as in an inserting machine require that a document is aligned relative to a particular station in the system prior to being processed at the station. Typically, this is accomplished by registering a particular edge of the document in a particular direction in the system. For example, documents must be aligned before being conveyed to a folding apparatus in order to achieve a proper fold. Also, enclosures which are to be inserted into an envelope should be aligned relative to the envelope prior to insertion in order to avoid processing difficulties. Furthermore, some documents which are to be transported away from a particular queuing station, to another adjacent document raceway, should be aligned at the queuing station relative to the raceway, in order to facilitate the processing of the documents.
Devices which register a particular edge of a document to a particular direction are known. See, for example U.S. Pat. Nos. 3,637,203, 4,078,790 and 4,925,180, which utilize stops that pivot into position to stop the advancement of documents being conveyed in a particular direction. Some registration devices, such as stationary side guides, perform the task of aligning the document while the document is being conveyed. Other devices, such as a "queuing" station, perform the dual task of aligning the document and stopping the document until tile next successive station is ready to receive the document for further processing. Typically, queuing stations comprise mechanisms which register the document by stopping, i.e., queuing the document. Queuing stations are typically configured to handle documents of a particular length and are not easily reconfigured to handle sheets of a different length.
Generally, during the stacking and registration of documents at a queuing station there is always the potential for the documents to become shingled, i.e., the top document in the stack is not directly above the lower documents but slightly shifted forward or backward, as they are conveyed from the queuing station.
Currently available commercial queuing stations include pinch rollers cooperating with transport belts to remove documents from the queuing station. The pinch rollers pivot into engagement with the stack of documents as the registration stops pivot out of the way. Although this arrangement has been found to reduce the shingling of the stack of documents, it has not eliminated such shingling.
In an attempt to eliminate such shingling, there is disclosed in U.S. Pat. No. 5,253,861 issued Oct. 19, 1993 to the assignee of the instant invention an improvement to a document registration apparatus that includes a plurality of laterally-spaced registration stops which pivot about a horizontal axis for stopping the motion of documents and registering the leading edge of the documents to a particular direction in the apparatus. The apparatus also includes at least one pinch roller cooperating with conveying structure for moving the registered documents away from the apparatus for further processing. The improvement includes structure for supporting the documents above the conveying structure when the documents are situated against the registration stops. The conveying structure includes a pair of transport belts and the supporting structure includes at least a pair of deck rails laterally positioned between the transport belts. A pair of pinch rollers urge the documents against the transport belts when the registration stops move away from the document path.
The aforementioned '861 improvement has been found to reduce shingling at the queuing station, but has not eliminated shingling. Shortcomings in the '861 improvement were noticed with thin paper, which sagged between the laterally positioned deck rails and contacted the transport belts. Thus, the lowermost sheet of thin documents was moved away from the queuing station before the pinch rollers urged the stack of documents against the transport belts. Thus, the stack of documents was not moved away from the queuing station in total registration but rather the stack had suffered the effects of shingling.
Accordingly, the instant invention provides a support for the paper and transport belts at the queuing station that is able to lift the registered sheets of paper of any thickness away from the moving belt surfaces to thereby eliminate any shingling effects in the registered sheets as they are moved away from the queuing station.